1. Field of the Invention
The invention relates to a stacked vehicle heat exchanger that performs heat exchange between a first heat carrier and a second heat carrier.
2. Description of Related Art
Stacked heat exchangers are well known. The stacked heat exchangers described in Japanese Patent Application Publication No. 10-300382 (JP-A-10-300382), Japanese Patent Application Publication No. 9-217992 (JP-A-9-217992), and Japanese Patent Application Publication No. 9-166391 (JP-A-9-166391) are examples. JP-A-10-300382, JP-A-9-217992, and JP-A-9-166391 describe stacked heat exchangers in which fluid (a heat carrier, a heat exchanging medium) passage tubes are formed in multiple stages by a stacked structure of thin metal plates. JP-A-10-300382, JP-A-9-217992, and JP-A-9-166391 also propose technology for discovering brazing defects in a joint portion through inspection, or technology for reliably (or easily) checking wrong assembly, and the like.
A stacked vehicle heat exchanger (such as a transmission fluid cooler) has also been proposed that has thin metal dish-shaped plates (i.e., a cup plates), of which the peripheral edge portions are fixed in a liquid-tight manner when stacked, formed such that a first layered space into which a first heat carrier (such as transmission fluid) is introduced and a second layered space into which a second heat carrier (such as coolant) is introduced, are formed alternately between them. This stacked vehicle heat exchanger performs heat exchange between the first heat carrier and the second heat carrier. In this kind of vehicle heat exchanger, inner fins are provided between the cup plates (i.e., in the layered spaces) in order to improve heat-transfer performance and ensure strength, for example. Also, a vehicle heat exchanger is manufactured by a core of the heat exchanger being formed by these cup plates and inner fins being alternately stacked together in order, and then being integrally brazed in a liquid-tight manner in a brazing furnace. Also, with this kind of vehicle heat exchanger as well, it is desirable to reduce wrong assembly, just as with the stacked heat exchangers described in JP-A-10-300382, JP-A-9-217992, and JP-A-9-166391. It is also desirable to improve cooling performance. In this way, there is room for improvement with regards to reducing wrong assembly and defects, and more reliably (or easily) performing an inspection for reducing wrong-assembly and defects. There is also room for improvement with regards to improving cooling performance and size reduction due to improved cooling performance. These issues are not well-known.